Air gun



Feb. 17, 1970 AIR GUN 2 sheets-sheet 1 Filed Aug. 25, 196'? INVENTOR Fb.17, 19170 j B. L. DE MARE/ 'AIR GUN I F11-ed Aug. 25, 19s? 2-sheets-'sheetl 2 INVENTOR azyf e0 mare United States Patent O 3,495,580AIR GUN Baltzar Leo De Mar, Aberdeen, Md., assignor to the United Statesof America as represented by the Secretary of the Army y Filed Aug. 25,1967, Ser. No. 663,452 Int. Cl. F41b 11 00; F41c 19/00; F41d 11/00 U.S.Cl. 124--11 8 Claims ABSTRACT F THE DISCLOSURE n struck by a springloaded plunger which is held in place by a remote controlled sear.

The invention described herein may be manufactured,

used, and licensed by or for the Government for governmental purposeswithout the payment to me of any royalty thereon.

Air guns are often used to facilitate studies of the ilight and impactcharacteristics of small projectiles, i.e. 22 to 60 caliber, at muzzlevelocities of from 150 to 800 feet per second.

Compressed air (or any equivalent gas) used in this type gun, as well asin a number of types of shoulder and handguns has a number of advantagesas follows:

(a) It is much easier to control the velocity as to magnitude andrepeatability with compressed air than with an explosive charge.

(b) Air (or equivalent gas) is clean and safe and does not foul the boreof the gun tube.

(c) It does not erode the gun tube.

(d) No special propellant storage facilities are required, as in thecase of explosive charges.

(e) Air guns are relatively quiet in operation, a desirable feature whenfiring in indoor ranges adjacent to oices and in laboratories.

While the gun of the present invention will be hereinafter described asan air gun, it is desired to use nitrogen gas as a propellant since itWill not form an explosive mixture in the presence of oil or greasewhich may be present in the mechanism. Nitrogen, also, will not promotecorrosion. This gas may be supplied to the valve mechanism from a tankwith an initial pressure of approximately 2300 p.s.i.

It is therefore an object of this invention to provide an air gun fortesting the ight and impact characteristics that is compact and easy ofoperation.

Another object is to provide an air gun having a balanced piston valveupon which a gas will act with equal force in opposite directions andywill move to iire the gun only upon application of an external forcethereon.

A further object is to provide an air gunin which the operating elementsare easily mounted or" dismounted for replacement thereof.

These and other objects and advantages ofthe present invention will befully apparent from the following description when taken in connectionwith the annexed drawings, in which:

FIG. l is a side elevation, partly in section, of the assembled air gunof the present invention, the tiring mechanism being in cocked position;

FIG. 2 is an enlarged view of the sear mechanism;

FIG. 3 is a cross section view taken along line 3-3 of FIG. l andlooking in the direction of the arrows;

FIG. 4 is an enlarged side elevation view of a modified form of valve;

FIG. 5 is an enlarged detail section of a further modification of avalve for use when using a uid as the propellant, and

FIG. 6 is a still further modified valve for the same use.

Referring in detail to the drawings in which life reference numeralsdenote like parts throughout, reference character 1 designates generallythe air gun of this invention and comprises a charging valve mechanism,generally indicated by 2, a spring actuated tiring mechanism, generallyindicated by 3, a gun barrel attachment generally indicated by 4, a baseupon which the aforesaid mechanisms are mounted, generally indicated by5, and

an air supplying system (FIG. 3) generally indicated by 6.

CHARGING VALVE MECHANISM The charging valve mechanism 2 consists of ahousing 7 having 'a longitudinal ibore 8 which is flared at its forwardend as at 9 to a larger diameter 10, as seen in FIG. l.

An :end closure 11 having an axial bore 12 is threadably engaged in therearward end of bore 8, as shown.

An air admission port 13 is disposed normal to bore 8 in housing 7, asshown in FIG. l.

A double-ended piston valve, generally indicated by 14 is slidable inbore 8. This valve comprises a stem 15 which extends rearwardly throughbore 11, as shown, and a block 16 is threadably engaged 0n its rearwardend.

Block 16 is notched at its upper surface as at 17 to provide means forthe engagement of a safety latch 18 which is pivotally mounted as at 19to a rod 20 threaded into housing 7.

A tooth 21 on the bottom of latch 18 normally engages in notch 17 andprevents forward movement of valve 14 in bore 8.

Latch 18 is biased downwardly by a spring 22, and is provided with ashoulder 23 normally engaging the rearward end of block 16.

Means to provide retraction of valve 14 are provided and consists of aclock spring 24 normally wound on a drum 25 and attached at its end to ayoke 26 iixed to the lower end of block 16 as shown.

The valve 14 is provided with a rst piston 27 at is forward end and isprovided with an annular groove 28 which receives an O-ring 29 therein.

A skirt 30 having ports 31 is also provided on the forward piston 27 asseen in FIG. l and slidably supports valve 14 and axial position whenpiston 27 moves into larger diameter 10.

A second piston 32 is provided on the rearward portion of stem 15 andhas annular groove 33 and which receive an O-ring 34 therein. Theforward end of housing 7 is provided with an annular ange 35 for apurpose to be described later.

SPRING ACTUATED FIRING MECHANISM Spring actuated iiring mechanism 3comprises a mounting block 36 having a longitudinal bore 37 in which atubular housing 38 is mounted.

Tubular housing 38 is closed at its forward endand this end is axiallybored as at 39. A cap 40 having an axial bore is threadably engaged onthe open end of housing 38.

A ring plunger 42 is slidable in bores 39 and 41 and extends beyondhousing 38 at both of its ends, as shown.

The rearward end of plunger 42 terminates in a cooking lug 42a having anannular groove 43 which is provided With a beveled forward wall 44. Lug42a is also beveled at its rearward end as at 45.

The forward end of 42 is urged in a forward direction by a coil spring93 encircling plunger 42 in housing 38 biases between cap 40 and a disc94 which is carried by plunger 42 and slides in tubular housing 38.

A sear mounting block 46 is spaced rearwardly from block 36 and isbifurcated at its upper portion to provide a pair of upstanding ears 47between which a sear 48 is pivoted as at 49 (FIG. 2).

Sear 48 is biased upwardly by a coil spring 50 in block 46, so that whenthe firing mechanism is cocked, it will engage in annular groove 43.

Sear 48 is further provided with a stud 51 which is normal to its sideand bears against one leg of a bell crank 52 which is also pivotedbetween ears 47 as at 53. The other leg of bell crank 52 is pivoted to atrigger rod 54 as at 55.

Rod 54 is slidable in a bearing block 56 which is provided with a safetyscrew 57 when it is desired to lock rod 54 against axial movementtherein.

A block 58 is threadably mounted on the free end of trigger rod 54 andis transversely bored at its end as at 59 to receive a ring 60 to whicha lanyard 61 may be attached. Block 58 also provides a stop which willbear against block 56 to limit forward movement of rod 54 therein.

A handle 62 is pivoted at 63 as shown and a pair of links 64 (one beingshown) are pivoted at 65 to a block 65a Which is slidable on ringplunger 42 and to handle 62 as at 66, providing a means of cocking thefiring mechanism 3.

Handle 62 is normally rotated in a counter clockwise manner by bias of atorsion spring 67 when not in use, and block 65a -Will act as a stop forlimiting forward movement of plunger 42 and handle 62.

GUN BARREL ATTACHMENT The gun barrel attachment 4 is for the purpose ofslidably supporting a gun barrel 68 and for its connection to housing 7.

A clamp 69 (one or more similar clamps will be employed throughout itslength) encircles barrel 68 and is secured thereon by bolts 70.

Short barrels will require two clamps, but the number will vary asdesired depending on the length of barrel.

Clamps 69 are bored as at 71 on their lower portions (only one side ofthe clamp being shown) and bores 71 receive a rod 72 therethrough (tworods are required).

Rods 72 are supported in mounting blocks 73, only one block shown (therewill be a block at each end of each rod for their support).

Gun barrel 68, when connected to housing 7, fits over a portion ofhousing 7 to bear against ilange 35.

A threaded collar 74 slidable on housing 7 is screwed over a threadedportion 68a on gun barrel 68 when it is desired to attach the barrel 68to housing 7.

When the collar 74 is tightened it pulls the gun barrel 68 rearwardlyagainst the flange 35, and the bore 75 of the gun barrel 68 will be inaxial alignment with bore of larger diameter in housing 7 as seen inFIG. 1.

BASE

The base 5 will be best seen in FIG. 3, and comprises a plate 76 towhich the valve mechanism 2, firing mechanism 3 and gun lbarrelattachment 4 are mounted by screws, welding, etc., in longitudinalarrangement, so that the gun barrel bore 75, bore 8 in valve housing 7and ring plunger 42 are in axial alignment as seen in FIG. 1.

Plate 76 is mounted to a slide 77 which has a runner 78 on each side sothat it may be mounted in ways 79 (Shown in broken lines) of a gunmount, not shown.

4 AIR SUPPLY SYSTEM The air supply system 6 is shown in FIG. 3 andconsists of an angle strip 80 mounted transversely on housing 7 andprovides supporting means for an air supply line 81 which may beconnected to a compressed air (or gas) tank, not shown.

Air line 81 leads into port 13 in housing 7. A charging valve 82 in airline 81 provides means for admitting or shutting off the air supply tobore 8 in housing 7.

An air exhaust line leading from bore 8 in housing 7 to the atmosphereprovides air escape therefrom.

A pressure gage 83 and a relief valve 84 are connected to line 85completing the air supply system.

Gage 83 and valves 82 and 84 are also supported by angle strip 80.

In FIG. 4, there is illustrated a modied valve in which the skirt 30 isdispensed with and a spider 86 substituted therefor.

Further modied valves are shown in FIGS. 5 and 6. Their construction isidentical, only the dimensions are changed.

Each valve has a forward piston head 96 instead of the O-ring in piston27. The heads have a beveled edge 87 which seats in a conical valve seat88 formed in an insert xed in housing 7.

In these forms, bore 8 is also changed in diameter.

Bore 8 is counterbored as at 90 at its forward end to provide a largerbore than 8 whereby the rearward piston 32 is of smaller diameter thanhead 86.

In FIG. 6, the bore 8 is the inverse of that shown in FIG. 5, bore 90abeing smaller than bore 8, so that the rearward piston 32 is larger indiameter than the head 96.

In both forms shown in FIGS. 5 and 6, the valve stem 15 is provided witha head 91 at its rearward end and a light coil spring 92 encircling stem15 replaces clock spring 24 (see FIG. 5).

Both modified forms use the piston head 96 in lieu of the O-ring 29which is likely to be washed off by outflowing fluid under highpressure.

In the case of the valve of FIG. 5 wherein the forward piston head islarger than the rearward piston 32, there will be a.relatively slightopening force, but this force is overcome by light spring 92.

In the case of the valve of FIG. 6 wherein the rearward piston 32 islarger than the forward piston 86, the higher the contained pressure,the greater is the sealing pressure of the forward piston 96.

In both modified forms, a comparatively low external force is sufficientto open the valve. When the fluid is discharged from the valve housing,the spring 92 will return the valve to its closed position.

If desired, the gun may be fired electrically by mounting a solenoid(not shown) on base 5, which will be attached to trigger rod 54 in lieuof lanyard 61.

OPERATION Operation of the air gun is simple. The barrel 68 is firstloaded. To load the gun barrel 68, collar 74 is unscrewed and barrel 68is moved forwardly on rods 72. After loading the barrel 68 is movedrearwardly until it abuts llange 35, and collar 74 is screwed overthreaded portion 68a and tightened.

The tiring mechanism 3 is then cocked by rotating handle 62 clockwisewhereby block 65a, sliding on plunger 42 abuts lug 42a and retracts theplunger 42. Upon rearward movement, bevel 45 on lug 42a rides over sear48 until it falls into groove 43.

A charge of pressurized air (or nitrogen) from a tank, not shown, isthen admitted to bore 8 in housing 7 by opening charging valve 82 untilthe desired pressure is read on gage 83.

Then the valve 82 is closed.

Since the piston valve 14 is balanced and is held in its closed positionby clock spring 24, it has no tendency to open under pressure as airpressure in bore 8 will act with equal force in opposite directions.

To fire the gun, lanyard 61 is pulled which disengages sear 48 by bellcrank 52 which pivots downwardly on stud 51, causing the firing plunger42 to be moved forward by spring 93 bearing against disc 94 on plunger42.

The forward end of plunger 42 in moving forward rides under a bevelededge 95 of latch 18 and lifts it upwardly. The plunger 42 then strikesblock 16 which, in turn, moves forward to slide valve rod 15 and pistons27 and 32 forwardly to open position where piston 27 enters enlargeddiameter 10 in bore 8.

The charge of pressurized air in bore 8 rushes through ports 31 in skirt30 and into the breech of the gun barrel to propel a projectile down thebarrel 68.

Spring 24 will now act to retract valve 14 to its closed position.

Air can be exhausted from housing 7 when desired by opening relief valve84 in case of malfunction of the gun, etc.

While only prefered forms of the invention are shown and described,other forms of the invention are conemplated and numerous changes andmodifications may be made thereon without departing from the spirit ofthe invention as set forth in the appended claims.

What is claimed is:

1. An air gun comprising in combination, a base, a valve housing havinga longitudinal bore therethrough mounted on said base, said bore flaringoutwardly at its forward portion to a larger diameter, there being anairport in said valve housing and communicating with said longitudinalbore, a closure having an axial bore mounted in the rearward end of saidlongitudinal bore, a valve stem slidable in said axial bore andextending a substantial distance rearwardly thereof, a first pistoncarried by the forward end of said stem and slidable in saidlongitudinal bore forwardly .of said airport, a second piston carried bythe rearward portion of said stem and slidable in said longitudinal borerearwardly of said airport, means carried by the forward portion of saidstem for axially supporting said first piston when moved into saidlarger diameter ,of said longitudinal bore, spring means connected tothe rearward end of said valve stem for urging said stem in a retractedposition whereby the forward end of said longitudinal bore is sealed bysaid l'irst piston, a gun barrel slidably mounted on said base and beingadaptable for detachable connection at its breech to the forward end ofsaid valve housing, a firing mechanism for activating said valve stemand pistons mounted rearwardly of said valve housing on said base, anair supply system connected to said valve housing adapted to supplypressurized air to said valve housing whereby when said valve stern andpistons are activated by said firing mechanism a burst of air isadmitted to said `gun barrel to propel a projectile when therein andmeans mounted on the rearward portion .of said valve housing to normallyrestrain said valve stern in a rearward position in said longitudinalbore until released by said firing mechanism.

2. An air gun as claimed in claim 1, wherein said means for supportingsaid first piston in said longitudinal bore comprises a tubular skirtfixed to the rearward end of said first piston and slidable therewith insaid longitudinal bore, there being a series ,of circumferentiallyarranged ports therein.

3. An air gun as claimed in claim 1, wherein said means for supportingsaid first piston in said longitudinal bore comprises a spider carriedby said valve stern and disposed adjacent the rearward end of said firstpiston and slidable therewith in said last named bore.

4. An air gun as claimed in claim 1, whe-rein said first and secondpistons comprise a piston head having a di ameter slightly less than thediameter of said longitudinal bore, there being an annular groove in thecircumferential surface of said heads and an O-ring in said groove ofeach head whereby said longitudinal bore is normally sealed on each sideof said air port.

5. An air gun as claimed in claim 1, wherein said first piston comprisesa piston head having a beveled inner edge, there being a conical valveseat in said housing to provide a valve seat for said inner edge whensaid mechanism is in closed position.

6. An air gun as claimed in claim 1, wherein the forward portion of saidlongitudinal bore is counterbored to provide a larger diameter than therearward portion and said first piston is correspondingly enlargedwhereby said rst piston has a larger sealing diameter than said secondpiston.

7. An air gun as claimed in claim 1, wherein the rearward portion ofsaid longitudinal bore is counterbored to Iprovide a larger diameterthan the forward portion and said second piston is correspondinglyenlarged whereby said second piston has a larger sealing diameter thanSaid first piston.

8. An air gun as claimed in claim 1, wherein said firing mechanismcomprises a tubular housing supported on said base rearwardly of saidvalve housing, a spring biased ring plunger having a cocking lug at itsrearward end, a sear mounting block mounted on said base rearwardly ofsaid tubular housing, a spring loaded sear rotatably mounted in saidblock and adapted to engage said cocking lug when said tiring plunger isin a cocked position, a spring biased cocking lever piVota-lly mounted`on said base rearwardly of said sear block, a block slidable on saidring plunger between said tubular housing and said cocking lug, a pairof links connecting said block on said plunger to said handle wherebywhen said handle is rotated clockwise, said block on said plunger willengage said cocking lug to move said plunger rearwardly and permit saidsear to engage said scar lug thereon and hold said plunger in saidcocked position, a bell crank rotatably mounted on said sear mountingblock and engaging said Sear, and a trigger rod mounted on said base andconnected at its forward end to said bell crank whereby when saidtrigger rod is pulled rearwardly said bell crank will rotate said searout of said cocking lug to permit said plunger to move forwardly toactivate said valve stem and pistons.

References Cited UNITED STATES PATENTS 2,304,841 12/ 1942 Mikkelsen124-11 2,574,408 11/1951 Moc 124-11 3,088,225 5/ 1963 Amistadi 124-113,254,640 6/1966 Sprouse 124-37 3,308,803 3/1967 Walther 124-37 FOREIGNPATENTS 1,108,641 1/1956 France.

519,143 3/1955 Italy.

711,542 7/ 1954 Great Britain.

RICHARD C. PINKHAM, Primary Examiner RICHARD W. DIAZ, AssistantlExaminer U.S. Cl. X.R. 124-34

